The Scientific Center for the investigation of the nature of luminescence and the mechanisms for creating radiation defects in alkali-halide crystals (AHC) with a symmetry of the lattice lowered was organized on the initiative of K.Sh. Shunkeev in 1984. With the direct support of academician Luschik Cheslav Bronislavovich, the laboratory acquired a scientific direction and was equipped with the necessary instruments for creating experimental facilities for absorption, luminescence and thermoactivation spectroscopy, as well as recording ion conductivity and thermostimulated crystal depolarization currents as the lattice symmetry decreases.
An universal cryostat, developed by us, was manufactured in the design bureau of the Institute of Physics of the University of Tartu of Estonia.
Directions of scientific research:
- Experimental studies by absorption, luminescent and thermoactivation spectroscopy methods, as well as recording of ionic conductivity and currents of thermally stimulated depolarization of crystals with decreasing symmetry of the lattice.
- Theoretical studies of the processes of autolocalization of electronic excitations in alkali-halide crystals with a decrease in lattice symmetry.
- Computer simulation of the mechanisms of formation of radiation defects in alkali-halide crystals with a decrease in lattice symmetry.
- Theoretical study and computer simulation of fluctuation superconductivity and current transport in loosely coupled superconductors.
- Development of technology for the compilation of a modern geological map for diatomite resources in the Aktobe region of the Mugalzhar district (“Zhalpak” area).
International cooperation is carried out with the following organizations:
University of Tartu (Tartu, Estonia),
University of Gdansk (Gdansk,Poland),
University of Latvia (Latvia,Riga),
Lomonosov Moscow State University (Moscow, Russia),
Ioffe physical-technical institute (Saint-Peterburg, Russia),
National Research Tomsk University (Tomsk, Russia),
Ural Federal University named after the First President of Russia B.N. Yeltsin (Yekaterinburg, Russia),
Kemerovo State University (Kemerovo, Russia),
National Laboratory Astana (Astana, Kazakhstan).
Academic mobility of students and faculty of the university with Gdansk (Poland) and Tartu (Estonia) universities is carried out.
2003-2005 "To conduct spectroscopic studies of the mechanisms of formation of point defects and their microstructure in ion-dielectric systems with a change in the symmetry of the lattice".
2006-2008 "Control of the luminescent properties of wide-band materials with a limited dimensionality when the lattice symmetry is lowered".
2009-2011 "Investigation of the properties of nanostructured radiation defects in ion-dielectric materials with a decrease in lattice symmetry over a wide temperature range".
2012-2014 "Development of a technology for controlling the physical properties of alkali-halide and superconducting materials with a decrease in lattice symmetry".
2013-2015 "Technology of accumulation of electricity based on alkali-halide crystals with a decrease in lattice symmetry".
2015-2017 "Technology of controlling the mechanism of energy transformation of ionizing radiation in alkali-halide crystals-scintillators".
2015-2017 "Development of a technology for controlling the optical properties of oxides, fluorides and alkali-halide crystals with a decrease in lattice symmetry to produce materials with specified luminescent characteristics".
In 2015, a contractual work was carried out with National Laboratory Astana on the theme "Development of a technology for compiling a modern geological map for diatomite resources in the Aktobe region of the Mugalzhar district (“Zhalpak” area).
On the basis of the scientific center, one doctoral (Shunkeev K.Sh.), eight candidate dissertations (Sarmukhanov E.T, Bekeshev A.Z, Tulepbergenov S.K, Sagimbaeva Sh.Zh., Myasnikova L.N, Barmina A.A, Sergeev D.M, Bizhanova K.B), two dissertations of Doctor PhD (Janturina N.N, Aimaganbetova Z.K).
The results of the research are published in more than 20 foreign journals with the impact factor "Physics State Solid", "Journal of Luminescence", "Journal of Physics:Condensed Matter", "Radiation Measurements", "Solid State Physics", "Journal of Applied Spectroscopy", "Russian Physics Journal", "Low Temperature Physics”.
1. Шункеев К.Ш., Сармуханов Е.Т., Бекешев А.З., Сагимбаева Ш.Ж. Криостат для деформации кристаллов в широком интервале температур (80-500 К) / Предпатент РК № 14831. опубл. 25.03.03. № 2003/0399.1.
2. Шункеев К.Ш., Сармуханов Е.Т., Бекешев А.З., Сагимбаева Ш.Ж. Способ усиления собственной люминесценции щелочногалоидных кристаллов / Предпатент РК № 14383. опубл. 08.07.03. № 2003/0937.1.
3. Шункеев К., Бармина А., Сармуханов Е., Бижанова К. Универсальный криостат для регистрации спектров поглощения кристаллов при низкой температуре под воздействием деформации и радиации // Патент РК № 26141. Заявка №2010/0304.1 Бюл. № 9 от 14.09.2012.
4. Шункеев К., Нурмагамбетов А., Бармина А., Мясникова Л.Н., Сергеев Д., Жантурина Н. Универсальный криостат для регистрации низкотемпературной ионной проводимости и токов термостимулированной деполяризации деформированных и облученных кристаллов // Инновационный патент на изобретение РК. заявитель Актюб. гос. ун-т им. К. Жубанова. – № 28731; бюл. №7 15.07.2014.
5. Шункеев К., Сергеев Д., Мясникова Л.Н., Бармина А., Аймаганбетова З.К. Способ определения низкотемпературных вакансионных дипольных дефектов в щелочногалоидных кристаллах методом термостимулированной деполяризации // Патент на изобретение РК. заявитель Актюб. гос. ун-т им. К. Жубанова. Опублик. 30.12. 2016. B(11) 31799; G01N 27/00 (2006/01)
Prizes and stipends:
The Satpayev Prize of the Ministry of Education and Science of the Republic of Kazakhstan (Shunkeev K.Sh., Sagimbaeva Sh.Zh., Tulepbergenov S.K., Bekeshev A.Z.)
State scientific scholarship of the Ministry of Education and Science of the Republic of Kazakhstan (Shunkeev K.Sh.)
State scientific scholarship of the Ministry of Education and Science of the Republic of Kazakhstan for young scientists (Sergeev D.M, Barmina A.A)
The state grant of the Ministry of Education and Science of the Republic of Kazakhstan "The best teacher of the university" (Shunkeev K.Sh.)
Prize of mayor of Aktobe region (Barmina A.A, Myasnikova L.N)
"The Best Young Scientist of the Aktobe region - 2016" (2nd place) (Myasnikova L.N, Zhanturina N.N, Sergeev D.M).
"The Best Young Scientist of the Aktobe region - 2017" (1st place) (Janturina N.N, Myasnikova L.N, Sergeev D.M, Barmina A.A)
The scientific management of dissertations of undergraduates of specialty 6М011000 - Physics and 6М060400 - Physics is conducted.
On the basis of the scientific center, based on the results of many years of work, four monographs were published:
Шункеев К.Ш. Люминесценция и радиационные дефекты в щелочногалоидных кристаллах при понижении симметрии решетки. – Актобе, 2012. – 516 с.
Шункеев К.Ш. Релаксация электронных возбуждений в щелочногалоидных кристаллах при понижении симметрии решетки. – Актобе, 2008. – 436 с.
Сергеев Д.М. Ангармонизм сверхпроводящего тока в джозефсоновских структурах. – Актобе, 2012.
Мясникова Л.Н. Люминесценция и экситон-фононное взаимодействие в щелочногалоидных кристаллах при низкотемпературной деформации». – Актобе, 2016. – 140 с.
1. Experimental installation methods based on absorption, luminescence spectroscopy and thermally activated, and the ionic conductivity and the thermally stimulated depolarization currents for investigating the nature and mechanisms of luminescence radiation defects in alkali halide crystals with decreasing lattice point defects uniaxial plastic and elastic deformation.
2. Made and patented a unique cryostat, allowing the crystal to deform at low temperatures in high technical vacuum mode and record their luminescence, absorption and thermal activation characteristics, and ionic conductivity and thermally stimulated depolarization currents.
3. The first detected and interpreted intensity enhancement effect of self-localized excitons in AHC elastic deformation at low temperature, based on which a new method of enhancing the intrinsic luminescence of alkali halide crystal without transforming excitation energy of an impurity to find modern scintillation counters.
4. The observed effect of intensifying the intrinsic luminescence of alkali-halide crystals is patented in the Republic of Kazakhstan. Registration number number 14383.
5. On the basis of the registration of thermally stimulated depolarization currents crystals cations activated light-polarizing currents homologues found that a reorientation of the dipole defects interpreted widely applicable to DC electricity storage.
6. The mechanism effectively create centers in the association of interstitials halogen by reducing local symmetry lattice AHC-field light homologues cation vacancy defects plastic deformation and elastic deformation of the low temperature voltage.
7. A new physical principle of assembling electron-hole pairs based on crystals activated with light impurities of sodium, substantially improving the scintillation characteristics of alkali-halide crystals, is applied in industry.
8. By the methods of silicate, spectrophotometric, X-ray diffraction, X-ray spectral, chemical, electron microscopic analyzes, the composition of diatom rocks by the area "Zhalpak" was studied. According to the results of studies, the value of the concentration of silica in natural diatomite is determined, which varies from 72.69% to 78.14%, which indicates the uniformity of diatomaceous rocks.
9. On the basis of scientific center "Radiation Physics of materials" for the technique of absorption spectra (maximum at 305 ÷ 335 nm), amorphous silicon (diatomite), and three oxidic components SiO2, Al2O3 and Fe2O3 using modern spectrophotometer «Evolution 300".
The setup allows the following optical characteristics of alkali-halide crystals to be recorded at low temperatures (liquid-nitrogen temperature 77K or -1960C):
X-ray-luminescence spectra in the range of 1.5-6.1 eV in automatic mode at various temperatures,
Spectra of tunnel luminescence in the range 1.5-6.1 eV in automatic mode at various temperatures,
Spectra of the flare of radiation defects with additional excitation by photons at the maxima of electronic color centers,
Simultaneously record both the integral and spectral components of the thermally stimulated luminescence.
The spectral range of the unit is determined by the MSD-2 monochromator, which records radiation from 200 nm to 850 nm. The development of the emission spectra in the range 200-850 nm (6.1-1.5 eV) was carried out in an automatic mode from the MSD-2 control panel with average speeds of 1; 2; 5; 10 and 20 nm / s.
Irradiation of the crystals is carried out from the RUP-120 X-ray unit in the 3 mA mode, 120 kW.
The cryostat makes it possible to measure the luminescence absorption characteristics of crystals (absorption, excitation, radiation, X-ray luminescence, thermally stimulated luminescence, tunnel luminescence, thermally stimulated depolarization currents, and ionic conductivity) both before deformation and under the action of elastic and plastic Deformations of various degrees (0 ≤ Ꜫ ≤ 10%) in a wide temperature range (80÷500 К).
The apparatus makes it possible to record ion conductivity and thermostimulated depolarization currents of crystals in a wide temperature range from 196°С to 350°С in the combination of a specialized cryostat that performs the regime of temperature and low-temperature deformation. The installation is assembled on the basis of the standard vacuum unit VUP-4. The level of technical vacuum is achieved by two steps: forvacuum pumping up to 10⁻² Торр and then - diffusion pump up to 10⁻⁵ Torr.
In the current spectra of thermos-stimulated depolarization of alkali halide crystals, polarization currents of dipole defects are detected. Such a method for recording the polarization dipole currents of alkali-earth metals in a wide temperature range (80÷500 К) after the action of plastic deformation creating a divacancy is designed as an application for an invention.
The technical result achieved in the present invention is a method for recording polarization dipole defects in alkali-halide crystals and determining their maximum disorientation temperature from the peaks of the current spectrum of thermally stimulated depolarization performed by linear heating of the crystal in the temperature range from 80K to 500 K.
Spectral complex in the spectral range from 180 nm to 1200 nm with a replaceable diffraction grating allows to record the spectra of optical absorption, excitation and radiation of substances (crystals, liquids and gases) and to trace the kinetics of these spectra in time. The need to use a highly sensitive luminescent method is dictated by the fact that absorption spectroscopy does not allow recording a small amount of radiation defects created by vacuum-ultraviolet radiation. The peculiarity of the experimental setup is the selective creation of electronic excitations in alkali-halide crystals when excited by photons of various energies, in contrast to X-ray radiation. The energy of the exciting photon is emitted by the MDR-23 monochromator, and the detection of the photons emitted by the crystals is detected by the MDR-4 monochromator. The source of the ultraviolet quantum is a xenon lamp, and the registrar is a solar-eyed photomultiplier.
The spectrophotometer makes it possible to analyze the optical absorption spectra of crystals in the spectral range 190-900 nm. The central unit of the installation is a metal cryostat, which maintains the temperature regime of the crystal in the temperature range 80÷500 К, and uniaxial deformation of the crystals takes place at these temperatures. Vacuuming the cryostat is carried out by a vacuum post (VP): first, the vacuum level is reached by at least 10⁻² Torr, and then switched to an adsorption pump cooled with liquid nitrogen (Т=80 К). Before the system is evacuated, the adsorption pump pre-regenerates by heating to 150-200° C with a constant evacuation by a fore-vacuum pump. As a result, the working vacuum of the cryostat reaches above 10⁻⁴ Торр, Torr, which is measured by the VIT-2 vacuum gauge. A special glass trap, cooled with liquid nitrogen, is connected between the vacuum pumps and the cryostat to filter from the vapors of the fore-vacuum pump.
The automatic recording spectrophotometer allows analyzing the transmission and optical absorption spectra of substances (crystals and liquids and gases) in the spectral range - 190-900 nm (6.5-1.4 eV). The device is equipped with a two-beam optical scheme in contrast to standard spectrophotometers. The built-in computer program provides scanning of spectra in a given spectral interval with different speeds and allows the development of time kinetics. It should be noted the peculiarity of the device that the optical density of substances is registered up to 4 units, when the existing analogous devices have only up to 1.4.